ALBERT

Notes: The decay rate of gamma radiation emitted by a Jamaican mineral spring was measured using portable rate meters. The results of these experiments, supported by auxiliary tests, suggested that the main radioelement causing the radioactivity was radon 222. Fluctuations in the intensity of the radiation were studied in situ. An inverse relation between the intensity and the discharge rate of water was established and the effect of rainfall and of earthquakes was investigated. Some suggestions are made concerning the possible source of radon.

Notes: The iron ores of the Siegerland-district are found in lodes occurring in schists of Lower Devonian age. In the course of the geophysical exploration for these ores, an attempt was also made to clarify the structure and the tectonics of the substratum of the sedimentary rock formations by seismic reflection measurements from the surface. Reflections were recorded in great numbers from layers of Silurian and Devonian age. The form of the folding of the strata derived therefrom corresponds well with that deduced from geological investigations. Beyond that, correlatable reflections were recorded from horizons down to a depth of nearly 25 000 m. It turned out that the iron ore lodes known from the mine workings occur almost vertically above those places where greater dislocations appear in the deepest substratum, and which geologically could be interpreted as fracture zones. The results so far obtained seem to be indicative of the fact that the tectonics of the deepest substratum and the occurrence of ore deposits are related to each other.

Notes: Precision calibration tests carried out with a Worden gravimeter in environment conditions as varied as possible have led to the following conclusions. The secular variation curve of the calibration shows that the secular relative variation has been very appreciable in the first year of life of the instrument, precisely of 1.3 × 10−3 in 13 months, while it has been practically zero in the second year. This must be ascribed to the fact that at the beginning of the operations the gravity-meter had just arrived from the factory with its measuring body renewed.On the other side the effect of 24°C of temperature difference between two series of determinations reveals itself in a variation of 0.0022 of the value of the calibration, so that it can be established that the variation of the calibration is I‰ for each 10°C of temperature variation.

Notes: Due weight must be given to three factors (1) its purpose, (2) the limitations imposed by nature, industry and environment, (3) the effect of errors in auxiliary measurements. Together the last two factors give an estimate of the accuracy which can be achieved. If this is sufficient for the instrument to fulfil its purpose design and construction can proceed. If it is not, a detailed survey of the last two factors is necessary in order to estimate the research effort that will be required when directed into the most effective channels. If the project is considered worth the effort it can proceed. These factors are discussed in relation to a borehole gravimeter. It is shown that the purpose will be served only if the accuracy is comparable with the best surface gravimeters. Borehole versions of some surface instruments are considered and it is concluded that none is suitable without considerable modifications. A successful borehole gravimeter is likely to be a completely new instrument.

Notes: Recently, quite good determinations of interfaces have been made by means of seismic well surveys. These were carried out for various oil companies in Northwest Germany, especially on salt-domes, and in Southern Germany, and in the area of the Upper Rhine Valley. It was the purpose to determine the configuration and position of salt-flanks and important planes of stratification in the neighbourhood of deep wells, and thus to reduce the risk of expensive wells.For the delineation of the boundary surfaces the method described by Gardner in “Geophysics 1949” was applied.The problems arising and the results obtained are discussed in connection with some interesting examples. From them we see, above all, that a knowledge as precise as possible of the seismic velocities of all media involved in the measurement is very important. A good idea of the general stratification in the area of deep wells seismically surveyed will make possible a rational and adequate planning of the survey program and will facilitate the interpretation.

Notes: A method is described in which the major part of gravimetric terrain corrections may be estimated by digital computing methods.

Notes: The electric and magnetic field of a direct-current element, embedded in a space consisting of two halfspaces differing in conductivity and permeability, is given in a form suitable for integration along a cable. From these formulae is obtained the field when one end of a D.C. cable is grounded in a highly conducting, pencilformed ore body, considered as a line electrode with uniform current leakage. Numerical examples are given for a horizontal line electrode. The formulae should be useful as a first approximation to the A.C. case. The validity of this is shortly discussed.

Notes: An analogy is established between the propagation of an electromagnetic field in a horizontally stratified conductive medium and that of currents in a linear electric network. This analogy will allow us to know in which case measurements executed at the surface of the ground can provide information about the properties of deeper layers. The situation is the same as when one tries, by means of impedance measurements at the input terminals, to know the properties of electric lines or lumped networks.A symmetrical linear network establishes between:Voltages V1 and V2 (respectively at input and output terminals)Currents I1 and I2 (respectively at input and output terminals), the relationship 〈displayedItem type="mathematics" xml:id="mu1" numbered="no"〉〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR77:GPR_77_mu1"/〉 is called the “phase constant” and Z the characteristic impedance The table 〈displayedItem type="mathematics" xml:id="mu2" numbered="no"〉〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR77:GPR_77_mu2"/〉 is called “characteristic matrix”If one then takes the horizontal components of an electromagnetic field, one can compare the voltage V with the horizontal electric field E (in volts m-1) and the current I with the horizontal magnetic field H (in Amp m−1)For plane waves in vacuum, one gets (Schelkunoff) Z=C (velocity of light)A layer whose thickness is D has a phase constant⌈= 2 πD/λ (λ= wavelength)For plane waves in a conductive, non magnetic medium whose conductivity is δ, one gets 〈displayedItem type="mathematics" xml:id="mu3" numbered="no"〉〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR77:GPR_77_mu3"/〉 For the system of waves created by a point-source one expresses the solution, since it is classical, as a sum or integral of different modes. For each of these modes, one can still write a bilinear relationship similar to (1), and calculate Z and ⌈.A generalization of this result is given.Boundary conditions that exist at the surfaces of separation are met by writing the continuity of E and H. This condition exactly corresponds to the fact that there one V and one I at the junctions of various sections of lines, or networks.The characteristic matrix of a cascade of networks-or here that of a horizontally stratified ground– is the product of the matrixes of each network. If, in addition, one knows the end impedance–here the conductivity λn of the last layer, supposed to be infinite–one can compute the input impedance Re of the whole system. In electromagnetic prospecting, it is Re that conditions the observable field.Inversely, if measurements were infinitely accurate, the. knowledge of the surface field would give all the thicknesses D and conductivities δ of intermediate layers, in the same way that impedance measurements at the input terminals of a cable would allow to locate any failure. The imperfection of measurements causes the elements located too far away (from the point of view of wave attenuation) to escape detection.

Notes: The iron ores of the Siegerland district are found in lodes occurring in schists of Lower Devonian age. These lodes, normally dipping almost perpendicularly, could be traced only by seismic reflection measurements underground, up to distances of approximately 500 m. The geophones were attached to the walls of the galleries. The frequencies of the recorded longitudinal and transverse waves ranged from 200 to 500 c.p.s. By this method a new siderite lode was discovered.

Notes: Book Reviewed in this article:Lehrbuch der angewandten Geophysik, Teil II, H. Haalck.

Notes: A series of repeat observations during a period of 5 years reveal a variation with time of the Worden gravimeter No. 142 small dial spring system. A possible change in the gravity difference concerned is ruled out. It is shown that the small dial scale factor has diminished by about 0.25 % within the last two years against about 0.5 % four to five years ago. The ratio of L.D. to S.D. has been analysed and the results obtained show confirmation of the change in the small dial system and prove a consistency in the large dial system.

Notes: A study is made of the possibility of calculating electric potentials, and therefore of interpreting apparent resistivity measurements, when the ground presents structural conditions more complicated than plane, parallel stratification.For this work a schematic type of structure has been chosen, in which the discontinuity planes for electric resistivity are both parallel and perpendicular to the level of the ground.The problem has been examinated in its general aspect, and then some criteria for the numerical calculation have been indicated.Some calculated examples are presented, relevant to vertical electric soundings accomplished by conventional technique, for particular types of structure.

Notes: The elastic impulse-from an explosion is propagated through the earth as an expanding shell bounded by the wavefront. This wavefront and its motion are a physical reality while rays or trajectories are much less sharply defined and cannot actually be observed because the wavelengths involved in seismic processes are too long. This means that the visualization and the interpretation of seismic processes can be carried out in a more satisfactory, simple and comprehensible way with wavefronts than with rays.H. R. Thornburgh (1930) introduced the very lucid and simple method of interpreting seismic refraction sections, using Huygen's principle to construct wavefronts from two symmetrical shotpoints by working back from their observed arrival times at the surface. The depths are found first with only a knowledge of the velocities down to the refractor and after that the velocities in the refractor can be determined.The pattern of the two wavefronts at equal time intervals, obtained when carrying out Thornburgh's construction, leads to the very simple, approximative “Plus-Minus” method. The additions of the travel times from two symmetrical shotpoints to-each geophone give the relative depths and their subtractions give the velocities of the refractor. The method extrapolates exact quantities from the refractor boundary up to the surface by the “Plus”- and “Minus” lines. This extrapolation introduces errors that can, more or less, be corrected for. A number of hypothetical cases are presented to give an insight into the applicability and reliability of the “Plus-Minus” method. Its main applications are for fairly shallow refraction investigations and for determining weathering corrections for refraction and reflection work.

Notes: Major savings for operators of seismic parties have been achieved by the use of prilled ammonium nitrate as a substitute for gelatin dynamite in areas where shot holes are dry. Pound for pound, the prills appear to have the same energy yield as 60% gelatin dynamite, and some improvement of records has been noted where prills are used. Safety problems are less with ammonium nitrate than with dynamite, and the development of efficient field handling techniques prevents the loss of production.

Notes: Some mathematical inequalities are proved and their relevance to the interpretation of local magnetic and gravity anomalies is discussed. They can be applied to the readings of either a vertical magnetometer or a total field magnetometer or a gravimeter and yield a maximum possible value for the depth below the earth's surface of the top surface of the body producing the anomaly.

Notes: The utilization of Scottish hill-land potential is severely limited by inadequate wintering facilities resulting from a low proportion of inbye land to hill-land. The machair lands of the Uists, in the Outer Hebrides, however, provide a more suitable ratio, which is not commonly found in the Highlands of Scotland.Investigations into the grassland problems of the Hebrides were intensified in 1955; and some of the data obtained from trials are given here, as are suggestions for improving the production and utilization of grass in these areas. The climate, soil, and agricultural system all interact to provide conditions which are rarely seen elsewhere.

Notes: A trial designed to show the effects of animal excreta on sward productivity is described.It was estimated that the grazing sheep returns in a season nutrients capable of immediate uptake by the plant equivalent to 5–6 cwt. nitro-chalk and 2–21/2 cwt. 60% muriate of potash per acre.A large part of sward yield depended on animal return. Clover depression from the effects of animal excreta and, under mowing treatment, from the effects of fertilizer nitrogen, did not result in marked loss of transferred clover nitrogen. There appeared to be a gain in clover soil-nitrogen from a reduction of the clover stand.A comparison is made between the restilts obtained from sheep excreta on the sward with those obtained from mowing treatment.The interaction between animal or fertilizer nitrogen and the clover plant is discussed.

Notes: Various forms of magnesium compounds were applied to grassland managed under modern intensive conditions and the effects on yield and composition of the herbage were measured. Magnesium limestone increased both yield and magnesium content. Commercial magnesite (MgO) increased the magnesium content rapidly and also gave a small increase in yield. An annual dressing of magnesium sulphate had little effect on magnesium content and tended to depress yield after two years.A marked seasonal effect exists in pasture magnesium content. Increasing the magnesium content had little effect on its distribution within the plant, but it tended to depress calcium and potash.The results are discussed with special reference to recent research on the magnesium metabolism in dairy cattle.

Notes: Three experiments are described, two with S215 meadow fescue and one with S37 cocksfoot, all grown for seed, during which all new tillers, soon after their appearance, were labelled at intervals of a month—a total of nearly 12,000 tillers. Whatever the first date of observation, the earliest tillers were always found to have contributed the largest proportion of the ears present at harvest. In one experiment applied nitrogen caused an increase in the number of tillers and ears, without however affecting the percentage contribution of the earliest tillers to the final crop of ears. The importance of the autumn period of tillering is stressed.

Notes: VOISIN, A. Grass Productivity.H. J. HINE. Machines on the Farm.

Notes: An experiment is described in which folding and sideways creep-grazing was compared with a rotational grazing management for lamb production at pasture.The experiment was carried out in two years (1957 and 1958) using a stocking-rate of 7 ewes and 12 lambs per acre from the birth of the lambs until they had all been sent for slaughter.The folding management produced more liveweight gain per acre (955 and 983 Ib.) than the rotational management (870 and 926 Ib.) and the mean carcass-weights were higher.The biggest differences, in favour of the sideways creep-grazing system, were in tbe quality of the carcass produced. Folding produced 74% and 77% grade A carcasses and the rotational management 43% and 53%, respectively, in 1957 and 1958.Worm-infestation was considerably less under the folding management and parasite control appeared to be more efFective where the area reserved for lambs only was not expanded to include ewe-grazed pasture as the season progressed.

Notes: The possibility of using microscopic characteristics of the leaf epidermis as aids to the identification of some British agricultural grasses in the vegetative condition has been investigated.The occurrence of the following types of differentiated cells on the leaf-sheath was markedly affected by the stage of growth of the tiller: silica cells, silico-suberose couples, cork cells, asperities and incipient asperities. These cells were frequently absent or confined to the base of the sheath in vegetative tillers, but they occurred over most of the sheath in culm leaves. Silica cells tended to preponderate in young tillers and silico-suberose couples and cork cells in the reproductive stage. The inter-nerve epidermis of the leaf-blade was generally the least affected by growth stage; although less differentiated than the sheath, it was found to be the most useful location for identification purposes. Species separable on the basis of the above-mentioned characters of the leaf-blade were:—〈list xml:id="l1" style="custom"〉(a)Tall fescue (Festuca arundinacea) from meadow fescue (F. pratensis)(b)Heath-grass (Sieglingia decumbens) from smooth-stalked meadow grass (Poa pratensis)(c)Sheep's fescue (F. ovina), from mat-grass (Nardus stricta) wavy hair-grass (Deschampsia flexuosa) and bristle-leaved bent (Agrostis setacea).Timothy (Phleum pratense), meadow foxtail (Ahpecurus pratensis) and bent (Agrostis spp.) were separable on the following characteristics, which were not affected by growth stage: the occurrence of crystal clusters precipitated by hot water in timothy and occasionally in meadow foxtail, but not in Agrostis species, the peculiar shape of undifferentiated cells of the nerve epidermis in Agrostis species, and the dense cover of asperities on the ligules of Agrostis spp. and Ahpecurus pratensis.

Notes: Three grasses, bromegrass, slender wheatgrass and reed canary grass were sown on irrigated land with Ladak alfalfa in varying ratios with the object of determining what effect different proportions of alfalfa to grass would have in preventing alfalfa domination. The total number of seeds, irrespective of the proportions used, was held constant at 2.5 per linear inch of row.The influence of alfalfa on total yield was such that no significant yield differences due to grasses were established. However, the relative stand of grass varied considerably in the different mixtures. Slender wheatgrass did not compete with Ladak alfalfa, and had nearly disappeared from all stands after five crop-years. Smooth bromegrass swards were dominated by the alfalfa, partrcularly where small amounts of the griass were sown. Reed canary grass and alfalfa maintained strong stands at all ratios of seed mixtures.The best overall ratio of grass to alfalfa by seed numbers was about 2.5: 1, although a higher ratio of grass was found desirable where brome was the grass component.Ratio of grass seed to alfalfa seed offered some measure of control for alfalfa domination, but choice of grass species was more important.

Notes: The proximate and ash constituents of twenty weed species have been determined. These weeds are all common to north-eastern England. Some are characteristic of hedgerow and roadside and a few species of arable land; the majority, however, usually occur in pasture and meadowland, or in other sites where they are freely accessible to stock. Exact locality, approximate stage of growth and date of harvesting are recorded.A comprehensive examination of their ash has been made and four trace elements of recognized importance, viz. iron, manganese, copper and cobalt, were determined.The weeds have been classified on the basis of a marking system, and it was found possible to place them in one or other of three fairly well-defined groups, viz. high, medium or low apparent value.Reference has been made to earlier assessments of these weeds and probable values, as reflected by chemical analysis, have been discussed. Most of the weeds listed as being of high apparent value are known or could justifiably be assumed to be of good nutritive status; examples of such are dandelion, nettle, creeping thistle and broad-leaved plantain. Ragwort, although ranked highly on the marking system used, is well-known to be toxic to animals. Not all members of the group of medium apparent value are likely to be eaten to any appreciable extent and at least two are of doubtful wholesomeness. Among weeds of low apparent value, only bird's-foot trefoil would appear to have much potential usefulness.

Notes: Sowings of annual meadow grass (Poa annua) were made in pots of soil which had been treated with sheep urine, with urine diluted × 50, or with water as a control. The treatments were applied before, at, and after sowing.Urine, whether applied at sowing time, or eleven days before or after, significantly reduced the germination or establishment of the weed grass.Diluted urine tended to reduce the number of established seedlings when applied at or shortly after sowing.In a subsidiary experiment the number of viable seeds in soil taken from pastures which had received no urine for four years were compared with those from soil under pastures receiving urine. The difference was not significant.

Notes: A new logging method, which makes use of specific chemical reactions to locate petroleum or other minerals has been developed. The method has been named “Differential Electric Log” (CED).In this paper the application to the CED method of redox (reduction/oxidation) reactions is discussed. A series of organic oxidants was found, capable of undergoing reaction with crude oil, sulphur, mineral sulphides, lignite. A small amount of an oxidant of this type is added to the drilling fluid and pumped into the borehole where reaction takes place in correspondence with layers containing oxidizable minerals. Two SP logs, recorded before and after the oxidation, are compared and the presence of such minerals is thus detected.A theoretical hypothesis explaining the mechanism of the potential change due to the chemical reaction is proposed both in the case of electronically conducting and non conducting minerals. The influence of redox potential on SP is discussed.The results of laboratory experiments on several different oxidizable ores and those of field tests performed on pyrite, lignite, and oil wells are reported on and discussed on the basis of the theoretical hypothesis proposed.

Notes: Ecological studies of Poa annua populations in turf using the core sampling method conducted over a period of several years showed that Poa annua was able to produce seed under frequent mowing at 1/2 to 3/4 of an inch. The population the second winter after seeding into Bermuda Grass turf was as high as that of the first.High soil moisture maintained by frequent light irrigations favoured its persistence in Bermuda Grass turf during the summer months.Matted Bermuda Grass turf which was lightly renovated in November contained a higher winter population of Poa annua than the non-renovated. Significantly denser populations were found in turf mowed at 1/2 to 3/4 of an inch than in turf mowed at 3 inches.Perennial prostrate growing strains were selected which could be readily propagated vegetatively and persisted in field plots for two to three years when clipped at 1/4 inch.

Notes: Four varieties of perennial ryegrass are compared throughout the seeding year and the first four harvest years (1954–58). Two of the varieties, Irish ‘commercial’ and New Zealand, are of ‘early’ type; and the others, Glasnevin and S23 are, ‘late’.New Zealand gave the most grazing, 1% more than ‘commercial’ and Glasnevin, and 5% more than S23.The ‘early’ varieties contrasted markedly with the ‘lates’ in seasonal growth.In persistency and in resistance to invasion by unsown species, the ‘lates’ were better than the ‘earlies’ S23 was outstanding, and New Zealand had an advantage over ‘commercial’. The ‘earlies’ were the more compatible with clover.New Zealand appears to have most merit, but sowing of more than one variety may give better results.

Notes: The object of the trial was to obtain information on productivity and persistence of 10 selected lucerne varieties subjected to a regular cutting treatment at an early and a very early stage of growth.The trial was established on the Company's land at Walsingham, Norfolk. The soil of the trial plots consisted of sand-loam topsoil (pH 6.9) and coarse sand subsoil (pH 7.5).

Notes: The changes in chemical composition during haymaking, the loss of nutrients in the field and during storage, and the nutritive value of swath-cured and tripoded hay were compared. In good weather no advantage was gained by tripoding the hay. The nutritive value of the hays made by the two methods was similar and the loss of dry matter in the field slightly lower in the swath-cured hay. In a bad season, however, the nutrient loss in the swath-cured hay greatly exceeded that occurring in the tripoded hay and the starch equivalent, as shown by the results of digestibility trials, was markedly lower for the swath-cured.

Notes: Studies of seed development and yield were conducted on three Aberystwyth varieties of timothy. The stages of seed development are described, as are their correlation with the external appearance of the head. Evidence is presented to support the suggestion that the latitude in the dale of harvest is greater than has hitherto been accepted. Population studies of seed crops have revealed that the abundant small heads (less than 4 cms. in length) contribute very little to the yield. The partition of the yield amongst the different inflorescence age-groups is given for each variety and methods of judging crop ripeness are discussed.

Notes: Cutting experiments on the spring growth of a stand of Provence lucerne, the first year of which were described in a previous paper (1), were continued For a second and third season.The value of taking the first cut at the early bud stage, particularly in an unfavourable season, was confirmed.No adverse effects were observed in the crop after three seasons of this treatment and yields were satisfactory in the third year.Similar cutting experiments were made on the second growth of an area of Du Puits lucerne after the spring growth had been cut uniformly at the early bud stage.The curves for protein and fibre production were similar to those for the first growth but the crop matured more quickly and yields were lower.No further advantage was observed in cutting the second growth before the flower stage although earlier cutting produced no apparent ill-effect on the plant or upon subsequent yield.

Notes: Normal-acid fibre content has been suggested as a useful indication of the digestibility of herbage. The changes in fibre content were therefore recorded during the spring and early summer of 1957 and 1958 to see whether regular differences occurred between species and varieties of herbage grasses.All species showed an increase in fibre content during spring and early summer, but considerable year-to-year fluctuations occurred: fibre content was also influenced by manuring and spacing. Regular differences between species and varieties have been detecled and, in perennial ryegrass, differences between individual genotypes. It should be possible to select breeding material for high or low fibre content if required.

Notes: During 1955–8 the technique of lucerne seed production was examined to compare the yield of seed and fodder under identical treatments on light and heavy soil. In addition, direct combine harvesting was compared with the tripod method.With the exception of the first year, which suggested certain advantages in seed production on light soil, the results obtained were not conclusive because of damage to the seed crop on light soil. The previous finding, that the best yield and quality of seed are secured from the first growth, were confirmed. It was shown that the aftermath could be cut in the autumn without a significant effect on the yield of seed, or persistency of the stand in subsequent years, and that the total yield of fodder was higher on heavy than on light soil.Direct combine harvesting of a seed crop after pre-harvest desiccation (4.8 lb. of D.N.O.C. in 30 gal. of water per acre), proved to be a satisfactory harvesting method when facilities for drying the seed were available.Observations on pollinating insects suggested that honey bees were mainly responsible for the amount of seed set.

Notes: This investigation was carried out with leafy varieties of perennial ryegrass at four centres near Aberystwyth over a period of three years. Nitrogen applied in spring increased lodging, the number of fertile tillers and also seed yield, except where sowing was made without a cereal cover crop. While reasonable yields were obtained from badly laid crops, it is suggested that lodging prior to anthesis has an adverse effect on seed yield. Clover included as a companion species tended to depress the yield of seed and increase the degree of lodging.Seed rate had less infiuence on lodging and seed yield, but the data show that similar yields were obtained from light seed rates of 4 lb. per acre as from the heavier rates. On the other hand, there was a tendency for the low rate of seeding to produce weedy plots, especially when sown in the absence of a cover crop.

Notes: The parasite-control value of keeping Nematodirus-infested pasture free from susceptible lambs for a complete year was examined in a controlled experiment. The practice was shown to be successful and confirmed previous recommendations, based on a knowledge of the parasite's life cycleThe detrimental quality of Nematodirus infestation was measurable by mortalities, depression of weight gains and the quality of the lambs. In the conditions of the experiment, the effects of Nematodiriasis approximately halved the liveweight production of affected animals.

Notes: MINISTRY OF AGRICULTURE, FISHERIES AND FOOD, ENGLAND AND WALES. Beef Production.SHELL CHEMICAL COMPANY LIMITED. Farm Weeds. An aid to their recognition.POEHLMAN, J. M. Breeding field erops.

Notes: Results are reported from six digestibility experiments in which frozen herbage was fed to groups of sheep at HIGH and Low levels of intake. The sheep on the HIGH level of intake digested the dry matter, organic matter, nitrogen and normal-acid fibre in the herbage less efficiently than those on the LOW level, confirming earlier results reported in Part VI of this series. Evidence suggests that this difference results from the higher rate of passage of food through the digestive tract at the HIGH level of intake.These results are discussed with reference to the errors introduced into the faecal-index method for estimating the digestibility of grazed herbage.

Notes: During the years 1956 and 1957, an attempt was made to assess the output of Irish Pastures using methods proposed by a Sub-Committee of the B.G.S. (9). It was found that the best results were obtained when output was determined on a single field, rather than on the whole farm basis. The yields showed highly significant correlations with both botanical composition and nutrient status of the pastures. The results were in agreement with the findings of others working on similar grasslands. It is suggested that the method might find a useful place in a programme either of advisory work or surveys concerned with grassland improvement.

Notes: An experiment conducted in south-west Scotland during 1956 and 1957 to investigate an outdoor method of rearing calves on pasture, with and without supplementary food, is described.Twenty-four Ayrshire bull calves were put on pasture at 2 weeks of age and received an average of 37 gallons of whole milk up to the time they were weaned at 8 weeks old. Twelve of the calves received no supplementary feeding, but the other twelve each ate 257 lb. of a meal containing oats, linseed cake, flaked maize and fish meal from their 3rd to their 20th week.The calves were moved around a series of plots (0.4 acre) which yielded an average of 1400 lb. of dry matter per acre at each grazing. The mean crude protein of the herbage dry matter was 17.4% in 1956 and 14.1% in 1957.The mean daily liveweight-gains of the calves from birth to 20 weeks of age were 1.05 lb. for the unsupplemented calves and 1.14 lb. for the supplemented ones—a non-significant difference, as was also the difference between the mean increases in belly-girth measurements of the two groups.Parasitic infestation of the two groups was extremely low and 83% of all faeces samples examined contained no worm eggs.The latest-born calves made the poorest liveweight gains.The outdoor rearing of calves is discussed.

Notes: Herbage, stubble and root weights were recorded for thirteen months on various leys subjected to two treatments differing in frequency of cutting.The root-weight per unit area of a ryegrass/white-clover ley was not affected by the frequency of cutting, but the less frequently cut plots had fewer tillers per unit area; the root- and stubble-weight per tiller was, therefore, higher on the less frequently cut plots, On a cocksfoot ley the root-weight was not affected by the cutting treatment, but in late summer and early autumn the stubble-weight was considerably higher on the less frequently cut plots.When cocksfoot was grown in rows 2 feet apart, the more frequent cutting decreased both the root- and stubble-weight.On grass leys root-weights were heaviest in the summer and thereafter decreased until the following spring.The root-weight of lucerne decreased from May to July, increased to a maximum in December and then decreased in weight. The changes in root-weight under lucerne leys were mainly due to changes in the weight of the tap-roots.The vertical distribution of roots was recorded, and, in the case of the cocksfoot in rows, the lateral distribution of roots is also given.

Notes: Constructional details are given of an inexpensive seed cleaner capable of handling material from single heads of timothy, yielding cleaned seed of over 98% purity by weight. The conditions within the cleaner are reproducible and running costs negligible.

Notes: The aim of this part of the investigation was to test in practice, on a small scale, the partial-wilting method of making silage and to obtain data on quality, losses and digestibility of the wilted and un-wilted products. Wilting of grass/clover herbage was carried out for periods of up to about 24 hours and, on average, the moisture content was lowered by 6–4%, from 80–4 to 74.0%. All silages were well preserved, there was no overheating, the wilted products showed considerably lower nutrient losses than the unwilted silages and were not lower in digestibility. Mould formation was much more extensive in the top layers of the wilted silages, except when the wilted material had been bruised.

Notes: Results are given of analyses made at the beginning of the second and third harvest years, 1956 and 1957, of swards produced from a standard seeds mixture sown under a wide range of ecological conditions.

Notes: Two leafy strains of cocksfoot, S143 and S37 were subjected to winter, spring and winter + spring defoliation; 2 cwt. per acre of nitro-chalk was applied after each defoliation, in addition to the standard manuring for all plots.Winter grazing of leafy cocksfoot does not appear to depress the yield of seed appreciably when extra nitrogen is applied.Grazing of cocksfoot in mid-April is likely to depress the seed yield substantially, especially if followed by a very dry summer.The reaction to hard defoliation by sheep may vary with the growth form of the cocksfoot strain.Grazing appeared to be more detrimental to seed yield than defoliation by cutting.During this investigation, prolonged frost which occurred during the early part of the year appeared to have an adverse effect on cocksfoot seed yield.

Notes: The possibilities of the wilting process have been investigated, with the ultimate object of determining its effect on the quality of farm silage. Attention has been confined mainly to mild or partial wilting, rather than severe wilting, since the danger of ensiling excessively dry material, especially when it is not chopped, is well recognised.Preliminary field tests were conducted to determine the rate and extent of the fall in moisture content in long and in bruised herbage, wilted for periods not exceeding 24 hours. Subsequently the wilted silages were made in experimental silos and, finally, in trench silos on a farm scale. This first paper deals with the field trials. Results show that important reductions in moisture content can be obtained in all but very poor weather. In good weather, moisture content may easily fall from the 80% to the 70% level; in poor weather (cool, overcast, with occasional showers) moisture loss still occurs.

Notes: Anisotropy measurements were carried out in two wells 300 km apart in the Northern Sahara, in order to improve the interpretation of seismic refraction surveys.These measurements were based on; the shortening of experimental oblique travel-times with respect to theoretical, travel-times computed by disregarding anisotropy. A perfect knowledge of the velocity distribution is required in order to eliminate all influence of refraction; therefore a continuous velocity log is indispensable.The results in the two wells are in agreement, and show that anisotropy is essentially a function of lithology. The following values were obtained: 〈displayedItem type="mathematics" xml:id="mu1" numbered="no"〉〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR202:GPR_202_mu1"/〉 Consequences pertaining to seismic refraction are as follows:— Depths computed without anisotropy are too small by 8 % to 9 %, i.e. about 300 meters.— The error on offsets reaches 70 %.— Depth computations carried out by assigning anisotropy factors at the sight of lithology gave very satisfactory results.— High velocity, highly anisotropic formations such as anhydrite play a very important part in the propagation of refracted waves and in interpretation.Consequences pertaining to seismic reflection are as follows:— Velocity profiles yield velocities closer to horizontal velocities than to vertical velocities.— Depth and migration computations are significantly influenced by high velocity, highly anisotropic formations such as anhydrite.

Notes: Book Reviewed in this article:Handbuch der Physik. Herausgegeben von S. Flügge.Der geologische Bau des Untergrundes von Schleswig-Holstein und seine Erdöllager-stätten.

Notes: Conventional or continuous velocity logging generally fail to solve the problem of velocities in the whole area of a seismic survey. Surface measurements often bring a large amount of additional information: effect of shallow layers, change of facies, correlations. The authors present a theoretical view on the physical meaning of interval velocities. After a short synthesis of the diverse formulae formerly proposed (Faust, West), the practical manner of using these formulae and the accurate interpretation obtained with the help of geological and geophysical data are shown. Several characteristical examples are finally explained and commented on.

Notes: A uniform field of the normal geomagnetic vertical intensity and its normal dependence on the first and second powers of latitude and longitude are derived for Europe and represented by sketches. The epochs of 1938.5, 1941.5, 1944.5, 1947.5, 1950.5, 1953.5, and 1956.5 have been chosen.It is suggested that anomalies of the vertical intensity should be given according to this field in order to obtain, in course of time, a coherent image of the magnetic effects of the European continent.

Notes: Solutions for the propagation of elastic waves at the surface of a cylindrical hole of infinite length are derived from the wave equation for a perfectly elastic and isotropic medium. It is found that the phase and group velocities depend on the ratio between the wave length and the circumference of the cylindrical hole. These surface waves can be classified into different orders. They differ in the calculated dispersion curves, in the range of possible wave lengths (cut-off-frequencies), and in the amplitude proportion of the components of the displacement vector. For very short wave lengths these waves converge to normal Rayleigh waves.These results are used to explain some of the multiple onsets and disturbances on seismograms, obtained in practical seismic investigations in the mines of Siegerland.The conformity of theoretical and practical results is limited, because the idealised suppositions on which the computation is based, such as perfect elasticity, homogeneous and isotropic medium, and circular cross section of the mine gallery are met only approximately in practice.